Hundreds of millions years ago, the
first tetrapods swan out of the water and began dwelling on land. About 50
million years ago, the ancestor of whales, Palicetids which is a wolf-life
predator, went back into the water and from then on whales are evolved. Just to
be clear the whales and wolves are not related.
Whales is a diverse group of aquatic animal. The closest living relative
of whales is hippo. A 28 million fossil proves that hippo is related to whale. There
is a 40 million gap between the early whales and early hippos, but a fossil of
28 million year found in Kenya proves the relation between the early whales and
early hippos.
Evolution of whales take place in its
body. The body of whales changed so it can be able to survive in marine
environment. The teeth of the whale evolved from large carnivorous teeth to
simple and the amount of teeth increased.
The pelvis bone and hind limbs
gradually became smaller because it is the vestigial structure of the whale.
The ears and nose also changed. The ears adapt to the sound of the water
because it is different from the land and the nose shifted to its forehead. All
these occurred so the whale have a better chance at surviving in the marine
environment.
There are many evidences that can prove
whale evolution such as fossils and embryos. The evolution of whale is an
evidence of transitional form. Transitional form is organisms’ changing states
between the ancestor’s form and the descendant’s form. Fossil evidences such as
the whale’s pelvis bone shows that the ancestor of the whale have hind limbs
and it is a land dwelling animal. As for the embryo evidence, whale embryo have
hind limbs, a long narrow tail and neck. This proves that the whale evolved
from land dwelling animal.
